Logical AND/logical OR
Others
2021-01-26 02:16:03
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Precedence and associativity of logical operators
- priority
- The priority of logical AND is higher than logical OR
- Example:
{
{true || false && false}}//truefirst calculate the logic and true || false
- Associativity
- Left associativity (operation from left to right)
In the logical AND and logical OR operators, if the data involved in the operation is not Boolean data, the return value has a characteristic
- Logical and
- If condition A is not established, return to condition A directly
- Example:
{
{0 && 1}}//0/{
{null && 0}}//null
- If condition A is established, regardless of whether condition B is established, return to condition B directly
- Example:
{
{1 && 0}}//0/{
{1 && 2}}//2
- Logical OR
- If condition A is established, return to condition A directly
- Example:
{
{1 || 0}}//1/{
{1 ||10}}//1
- If condition A is not established, regardless of whether condition B is established, return to condition B directly
- Example:
{
{0 || null}}//null/{
{0 || 996}}//996
Short-circuit phenomenon of logical AND and logical OR
- Logical AND: condition A is not established, return condition A directly, condition B will not be executed
- Example
let num = 1;let res = (10 > 20) && (++num);console.log(res, num);//false,1
- Logical OR: Condition A is established, condition A is returned directly, condition B will not be executed
- Example
let num = 1;let res = (10 < 20) || (++num);console.log(res, num);//true,1
Origin blog.csdn.net/big_sun_962464/article/details/112128448